The present invention relates to a scraping apparatus as well as a scraping method for scraping a surface of a work to be machined and more particularly, to a scraping apparatus as well as a scraping method for scraping a surface of a work to be machined to form a large number of recesses functioning as oil grooves on the surface of the work as a sliding surface.
A scraping process based on the conventional technology for forming a number of recesses as oil grooves on a surface of a work to be machined has generally been performed by scraping the surface of the work with a scraper like a flat chisel. The scraping process described above automatically performed by attaching a scraper to a machine tool for numerical control, a main shaft of a machining center, or to an end of an arm of a machining robot by an automatic control machine without manual works is disclosed in Japanese Patent Laid-Open Publication No. HEI 5-123921, Japanese Patent Laid-Open Publication No. HEI 7-1229, and Japanese Patent Laid-Open Publication No. HEI 8-187620.
Disclosed in Japanese Patent Publication No. SHO 56-152539 is a scraping method for forming a number of recesses as oil grooves on a surface of a work to be machined by hardening the surface of the work in a grid pattern by a laser beam and polishing the surface of the work, and this method is effective because, after the process, a portion other than that of the grid pattern is polished more than the portion of the grid pattern due to a difference of surface hardness between the two portions.
FIG. 11 and FIG. 12 show a machining center for executing the scraping method disclosed in Japanese Patent Laid-Open Publication No. HEI 7-1229. In FIG. 11 and FIG. 12, designated at the reference numeral 100 is a base, at 101 a column provided on the base 100, at 102 a main-shaft base movably provided in the column 101 in the Y-axial direction (direction vertical to a paper surface) as well as in the Z-axial direction (vertical direction), at 103 a main shaft provided on the main-shaft base, at 104 a hand scraper attached to the main shaft 103 and having a scraper 105 with a flat blade, at 106 a work table movable in the X-axial direction with a work W mounted thereon, and at 107 an NC unit for providing controls over the main shaft as well as each axis of the X-axis, Y-axis, and Z-axis.
The hand scraper 104 incorporates therein a swinging mechanism, and swings the scraper 105 along the direction indicated by the arrow A (Refer to FIG. 12).
In the machining center as described above, the scraper 105 of the hand scraper 104 is swung in the direction indicated by the arrow A under the controls of the main shaft as well as controls in directions of the X-axis, Y-axis, and Z-axis by the NC unit 107, and with this feature the scraping process having the same precision as that obtained through manual works by a highly skilled worker is automatically performed over a specified area on the surface of the work without the manual works.
Although the conventional type of scraping process can be automated, any of the processes is carried out by cutting or polishing the surface with a tool, so that, when a surface to be machined is extremely hard, a long time is required for machining, and if a super hard material is to be machined, a costly scraper has to be used, which causes increase of the machining cost. Also, a high-precision scraping process requires high-precision calibration of the tool due to abrasion or the like is required, so that obtained scraping precision is restricted.
Also, a form of an oil groove or of a pattern in the scraping process is restricted by a form of a tool, and for this reason, sometimes an oil groove or a pattern in a desired form can not be carried out.
It is an object of the present invention to obtain a scraping apparatus as well as a scraping method which efficiently carries out a high-precision scraping process regardless of hardness of a work to be machined and without requiring a costly scraper and has high flexibility in selection of a form of an oil groove or a pattern in the scraping process.
With the scraping apparatus according to the present invention, a scraping process is executed on a surface of a work to be machined to form recesses thereon by irradiating a converged laser beam onto the work relatively moving to the laser beam for removing some portions by being melted or evaporated from the surface thereof, so that a high-precision scraping process can efficiently and automatically be performed regardless of hardness of a work to be machined and without requiring a costly scraper, and also a scraping process having high flexibility in selection of forms for an oil groove or a pattern can be performed according to a machining program for numerical control.
With the scraping apparatus according to the present invention, in an NC laser apparatus having a laser machining head as well as a work table relatively movable along coordinate axes to a work to be machined, a scraping process is performed on a surface of a work to be machined on the work table to form recesses thereon by irradiating a laser beam onto the work through the laser machining head and removing some portions by being melted or evaporated from the surface thereof, so that a high-precision scraping process can efficiently and automatically be performed regardless of hardness of a work to be machined and without requiring a costly scraper, and also a scraping process having high flexibility in selection of forms for an oil groove or a pattern can be performed according to a machining program for the NC laser machining apparatus.
With the scraping method according to the present invention, there is a step of scraping a surface of a work to be machined to form recesses thereon by converging a laser beam outputted from a laser oscillator by a converging lens and irradiating the converged laser beam onto the work relatively moving to the laser beam for removing some portions by being melted or evaporated from the surface thereof, so that a high-precision scraping process can efficiently and automatically be performed regardless of hardness of a work to be machined and without requiring a costly scraper, and also a scraping process having high flexibility in selection of forms for an oil groove or a pattern can be performed according to a machining program for numerical control.
With the scraping method according to the present invention, in an NC laser apparatus having a laser machining head as well as a work table relatively movable along coordinate axes to a work to be machined, there is a step of scraping a surface of a work on the work table to be machined to form recesses thereon by irradiating a laser beam onto the work through the laser machining head and removing some portions by being melted or evaporated from the surface thereof, so that a high-precision scraping process can efficiently and automatically be performed regardless of hardness of a work to be machined and without requiring a costly scraper, and also a scraping process having high flexibility in selection of forms for an oil groove or a pattern can be performed according to a machining program for the NC laser machining apparatus.
Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.